Parametric finite element modeling and topology optimization for stress reduction of spatial pipeline based on beam/solid element coupling

To efficiently perform the topology optimization for stress reduction of the pipeline system, this paper innovatively proposes a parametric finite element modeling (PFEM) method for pipeline systems based on beam/solid coupling. Furthermore, the multiple straight-line segment lengths are selected as the design variables, and a topology optimization method for stress reduction is proposed. For the PFEM, the incompatible solid (Solid-NC) element and three-dimensional (3D) Timoshenko beam element are implied to simulate the mechanical characteristics of the constrained and unconstrained regions of the pipeline, and then the beam/solid element coupling is realized by the penalty function method. The parametric geometric relationship of the pipeline system and the node coordinates of the finite element model are solved by the direction vector and vector decomposition methods, and the PFEM of the pipeline system is achieved and verified by ANSYS. Finally, the stress reduction optimization model of the pipeline system is established, and the stress reduction optimization of an actual pipeline is implemented using the particle swarm algorithm. The optimization results show that the maximum stress response of the optimal pipeline shape is 5.5 times lower than that before optimization, which shows the rationality of the optimization method.